The present invention relates to surgical tools and procedures generally and relates more particularly to the use of electrosurgical ablation to treat atrial fibrillation.
In patients with chronic atrial fibrillation having tachycardia that resistant to medical treatment, the Maze III procedure has been employed. This procedure controls propagation of the depolarization wavefronts in the right and left atria by means of surgical incisions through the walls of the right and left atria. The incisions create blind or dead end conduction pathways, which prevent re-entrant atrial tachycardias from occurring. While the Maze procedure is successful in treating atrial fibrillation, the procedure is quite complex and is currently practiced by only a few very skilled cardiac surgeons in conjunction with other open-heart procedures. The procedure also is quite traumatic to the heart, as in essence the right and left atria are cut into pieces and sewed back together, to define lines of lesion across which the depolarization wavefronts will not propagate.
It has been suggested that procedures similar to the Maze procedure could be instead performed by means of electrosurgical ablation, for example, by applying RF energy to internal or external surfaces of the atria to create lesions across which the depolarization wavefronts will not propagate. Such procedures are disclosed in U.S. Pat. No. 5,895,417, issued to Pomeranz, et al., U.S. Pat. No. 5,575,766, issued to Swartz, et al., U.S. Pat. No. 6,032,077, issued to Pomeranz, U.S. Pat. No. 6,142,944, issued to Swanson, et al. and U.S. Pat. No. 5,871,523, issued to Fleischman, et al, all incorporated herein by reference in their entireties. Hemostat type electrosurgical or cryo-ablation devices for use in performing such procedures are described in U.S. Pat. No. 5,733,280 issued to Avitall, U.S. Pat. No. 6,237,605 issued to Vaska, et al, U.S. Pat. No. 6,161,543, issued to Cox, et al., PCT published Application No. WO99/59486, by Wang and in pending U.S. patent application Ser. No. 09/747,609 filed Dec. 22, 2000 by Hooven, et al., all incorporated herein by reference in their entireties. In order for such procedures to be effective it is desirable that the electrosurgically created lesions are continuous along their length and extend completely through the tissue of the heart. These goals may be difficult to accomplish employing dry ablation electrodes or electrodes applied only to the interior or exterior surfaces of the heart tissue.
According to the present invention, a maze type procedure may be performed using a set of bipolar electrosurgical hemostats, which apply ablation energy (e.g. RF energy) across the walls of the left and right atria by means of delivery means (e.g. electrodes) located on either side of the atrial walls. In a preferred embodiment of the invention, the hemostats are provided with elongated RF electrodes having various straight and curved configurations. In the particular embodiment of the invention described herein, a collection of straight and curved bipolar electrosurgical hemostats is provided in order to allow the physician to produce lines of lesion that approximate the incisions that would occur during the Maze III procedure as described in the book xe2x80x98Cardiac Surgery Operative Techniquexe2x80x99 by Donald B. Doty, M.D. at pages 410-419, incorporated herein by reference in its entirety, and hereafter referred to as the xe2x80x9cDoty referencexe2x80x9d. Other specific sets of hemostats may correspondingly be provided according to the invention to allow approximation of lines of lesion of the incisions that would be provided by other forms of the Maze procedure.
The invention as disclosed herein is describing the context of an open chest surgery, with patient undergoing cardiopulmonary bypass. As described, the procedure does include a limited number of surgical incisions, in conjunction with the creation of various straight and curved lesions using the bipolar electrosurgical hemostat set of the present invention. However, the present invention is also believed applicable to closed chest procedures, in which the heart is observed thoracoscopically and access is provided by means of thoracoscopic surgical ports. It is believed that ultimately, the invention may also applicable to closed chest, beating heart surgery, dispensing with the necessity of cardiac bypass.